Films and Scans
Several ambulances arrive back-to-back late one evening. After working up an elderly man with pulmonary edema and a woman with a broken hip you arrive at the third patient, a sixty-something woman with a story of stomach pains since this morning. In between stabilizing the pulmonary edema guy and making sure the hip is being worked-up to Ortho’s satisfaction, more history trickles in on the stomach pain woman. Her pain began abruptly, is no better, and has been fairly unrelenting. It is a new problem. “I feel like my stomach as blown up like a balloon,” she notes. “I tried to eat something, but everything comes right back up.” Her husband, sitting at the bedside, grunts in assent. The patient has no PMH, allergies or meds. Vitals look good. Her abdomen is diffusely tender with some guarding, and a bit distended.
“Well, Ma’am,” you say, “it might be your gallbladder acting up.” With these symptoms you are worried she is developing cholecystitis or gallstone pancreatitis. “We’ll get a CT scan and take a look.” You don’t bother mentioning that ultrasound is not available after sundown in this hemisphere. You consider a vascular dissection study, but decide that the non-contrast scan will be the first stop. Labs are drawn and pending.
By the time you finish admitting pulmonary edema man and the hip fracture case the CT scan on the suspected gallbladder case is complete. What does it show ?
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This case underscores that although gallstone disease will start abruptly, so will an acute perforated viscus (and also an acute vascular dissection). The patient’s description of feeling “blown up like a balloon” seems prescient in retrospect – she hit the nail right on the head. Surgical exploration later confirmed a perforated peptic ulcer.
The CT scanning shows a massive amount of free air extending from the sub-diaphragmatic area nearly to the pelvis. It is layered anteriorly, due to the position of the patient flat on her back in the scanner. This large amount of air cannot be mistaken for bowel. If there is a question, note that the side-angles of the air pocket are very acute (not rounded off like bowel). Also, free air will highlight other structures such as bowel and solid organs, in the case of bowel sometimes leaving them partly or completely suspended in an air pocket (see large arrow). As a bonus, a small amount of free fluid is also seen (labeled).
Use of non-contrasted CT scanning, rather than traditional multi-contrast CT, has permitted this diagnosis to be made rather quickly. Admittedly, this amount of air would have certainly shown up on abdominal films. However, at my hospital, it is faster to get a non-contrast CT scan rather than 4 abdominal X-rays in various positions – plus you get more data. A drawback of this strategy would be the need to repeat the CT with either IV or oral contrast. The IV contrast might be needed if a dissection were suspected but not seen on the initial non-contrast study. Most AAA’s with leak will be diagnosed on non-contrast CT. In most cases the oral contrast does not add much to the study’s accuracy or utility from the ED’s perspective (although many surgeons and radiologists still favor this approach). Back at the room, you bring the patient and family up to date.
“The good news is that we know what is wrong with you, and the bad news is that we know what is wrong with you.” You explain about the probable peptic ulcer and the need for surgery with as little delay as possible.
“Thank you, doctor, you’ve been very kind. By the way,” she adds as you turn to leave the room, “you don’t think this has anything to do with all those Motrin I have been taking for my rheumatism, do you?” Twelve over-the-counter tabs per day. Ouch.
John Dallara, MD, directs the Emergency Medicine PREP Course